Hello. I own a CFW10 filter wheel. One of the filters i am using is an SA200 star analyzer to get low resolution spectrums. The SA200 fits well within the wheel but some improvements are desireable. First of all, the SA200 works better if its distance to the chip is increased. To accomplish that, i ordered a few laser cut plates (attached IMG_5) and stacked them to increase the CFW10 casing as desired (IMG_4) . In my case, round about 40 mm. Another enhancement would be to attach a small prism and a IR/UV filter to the SA200. Doing this the profile of the filter grows a lot and it will hit the motor casing when the wheel turns. To avoid this i bought a shaft expansion (IMG_3) for the motor and raised the motor as needed (IMG_1). So far it seemed to work pretty well, but when i tried it with CCDSoft, the fiter positions were changed one place, that is, when imaging with V filter, the filter wheel moved to the filter next to it, filter R. And the same happened with all slots except with number one, that stopped in an awkward position as seen in attached IMG_2. So i dissassembled the shaft extension and went back to the normal motor position and all was back to normal functioning. My question is, why is this happenning? Motor shaft has a 1.95 mm diameter while shaft extension changes this to 2.85. I guess this would be the culprit? Finding the proper shaft extension is very difficoult. If i manage to file down to 1.95mm the one i already have, will this fix the problem? Thanks for advices! IMG_2 and IMG_5 will be attached in the next message. David Cejudo Observatorio El gallinero El berrueco, Madrid (Spain).